The butterfly genus Cycnus is now synonymized with Panthiades.
In Greek mythology, several characters were known as Cycnus (Ancient Greek: Κύκνος) or Cygnus. The literal meaning of the name is "swan", and accordingly most of them ended up being transformed into swans.
Cycnus, son of King Ederion (Ancient Greek: Ἐδερίων) or Eredion of Achaea, who, in the 6th century CE account of John Malalas, seduced Leda and made her mother of triplets: the Dioscuri and Helen.[5] In all other sources, she had these children by Zeus who approached her in the shape of a swan (kyknos). For more information, see Leda and the Swan.
Cycnus, a blunder for Guneus in the manuscript of Hyginus[8] (list of the Achaean leaders against Troy).
According to Pseudo-Eratosthenes and Hyginus' Poetical Astronomy, the constellation Cygnus was the stellar image of the swan Zeus had transformed into in order to seduce Leda[9] or Nemesis.[10]Pausanias and Servius state that Apollo turned Cycnus of Liguria into a swan after the death of his lover Phaeton, then later placed him among the stars as the constellation Cygnus.[11][12][13]